From 06ff8708f0b834cf1b35afa46113c6c973905cad Mon Sep 17 00:00:00 2001
From: Max Filippov <jcmvbkbc@gmail.com>
Date: Sat, 12 Dec 2020 12:14:40 -0800
Subject: [PATCH] gcc: xtensa: fix PR target/98285

2020-12-14  Max Filippov  <jcmvbkbc@gmail.com>
gcc/
	* config/xtensa/predicates.md (addsubx_operand): Change accepted
	values from 2/4/8 to 1..3.
	* config/xtensa/xtensa.md (*addx, *subx): Change RTL pattern
	to use 'ashift' instead of 'mult'. Update operands[3] value.

gcc/testsuite/
	* gcc.target/xtensa/pr98285.c: New test.
---
 gcc/config/xtensa/predicates.md           |  5 +--
 gcc/config/xtensa/xtensa.md               | 18 +++++---
 gcc/testsuite/gcc.target/xtensa/pr98285.c | 54 +++++++++++++++++++++++
 3 files changed, 68 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/xtensa/pr98285.c

diff --git a/gcc/config/xtensa/predicates.md b/gcc/config/xtensa/predicates.md
index 1721640dc79e..eb52b05aafad 100644
--- a/gcc/config/xtensa/predicates.md
+++ b/gcc/config/xtensa/predicates.md
@@ -25,9 +25,8 @@
 
 (define_predicate "addsubx_operand"
   (and (match_code "const_int")
-       (match_test "INTVAL (op) == 2
-		    || INTVAL (op) == 4
-		    || INTVAL (op) == 8")))
+       (match_test "INTVAL (op) >= 1
+		    && INTVAL (op) <= 3")))
 
 (define_predicate "arith_operand"
   (ior (and (match_code "const_int")
diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 749fe477d562..671c4bea144f 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -162,11 +162,14 @@
 
 (define_insn "*addx"
   [(set (match_operand:SI 0 "register_operand" "=a")
-	(plus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
-			  (match_operand:SI 3 "addsubx_operand" "i"))
+	(plus:SI (ashift:SI (match_operand:SI 1 "register_operand" "r")
+			    (match_operand:SI 3 "addsubx_operand" "i"))
 		 (match_operand:SI 2 "register_operand" "r")))]
   "TARGET_ADDX"
-  "addx%3\t%0, %1, %2"
+{
+  operands[3] = GEN_INT (1 << INTVAL (operands[3]));
+  return "addx%3\t%0, %1, %2";
+}
   [(set_attr "type"	"arith")
    (set_attr "mode"	"SI")
    (set_attr "length"	"3")])
@@ -196,11 +199,14 @@
 
 (define_insn "*subx"
   [(set (match_operand:SI 0 "register_operand" "=a")
-	(minus:SI (mult:SI (match_operand:SI 1 "register_operand" "r")
-			   (match_operand:SI 3 "addsubx_operand" "i"))
+	(minus:SI (ashift:SI (match_operand:SI 1 "register_operand" "r")
+			     (match_operand:SI 3 "addsubx_operand" "i"))
 		  (match_operand:SI 2 "register_operand" "r")))]
   "TARGET_ADDX"
-  "subx%3\t%0, %1, %2"
+{
+  operands[3] = GEN_INT (1 << INTVAL (operands[3]));
+  return "subx%3\t%0, %1, %2";
+}
   [(set_attr "type"	"arith")
    (set_attr "mode"	"SI")
    (set_attr "length"	"3")])
diff --git a/gcc/testsuite/gcc.target/xtensa/pr98285.c b/gcc/testsuite/gcc.target/xtensa/pr98285.c
new file mode 100644
index 000000000000..2c037d546565
--- /dev/null
+++ b/gcc/testsuite/gcc.target/xtensa/pr98285.c
@@ -0,0 +1,54 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int mul3(int v)
+{
+  return v * 3;
+}
+
+int mul5(int v)
+{
+  return v * 5;
+}
+
+int mul7(int v)
+{
+  return v * 7;
+}
+
+int mul9(int v)
+{
+  return v * 9;
+}
+
+int mul2sub(int a, int b)
+{
+  return a * 2 - b;
+}
+
+int mul4sub(int a, int b)
+{
+  return a * 4 - b;
+}
+
+short index2(short *p, int i)
+{
+  return p[i];
+}
+
+int index4(int *p, int i)
+{
+  return p[i];
+}
+
+long long index8(long long *p, int i)
+{
+  return p[i];
+}
+
+/* { dg-final { scan-assembler-times "addx2" 2 } } */
+/* { dg-final { scan-assembler-times "addx4" 2 } } */
+/* { dg-final { scan-assembler-times "addx8" 2 } } */
+/* { dg-final { scan-assembler-times "subx2" 1 } } */
+/* { dg-final { scan-assembler-times "subx4" 1 } } */
+/* { dg-final { scan-assembler-times "subx8" 1 } } */